TWI476820B - Method to improve uniformity of chemical mechanical polishing planarization - Google Patents

Description

Method for improving the uniformity of chemical mechanical polishing flattening

This invention relates to ion implantation, and in particular to the results of improving chemical mechanical polishing processes with ion implantation.

Chemical mechanical polishing (CMP) is widely used in the manufacture of integrated circuits (ICs) as a method of removing materials to planarize the surface of an IC. Flattening can make photolithography accurate or improve the steps of other IC processes. The CMP process can involve two aspects: the chemical reaction of the material and the physical wear. To remove material, the CMP process can use a polishing pad in the grinding equipment. In this CMP process, the polishing pad or workpiece can be rotated. In one example, the surface of the workpiece can be brought into contact with a rotating pad that is saturated with a slurry of at least one abrasive particle or a reaction solution that chemically reacts with features of the surface of the workpiece. In one example, a force can be applied simultaneously between the workpiece and the polishing pad to perform this step.

CMP is used for planarization, formation of features, or formation of damascene interconnects. The planarization can include an oxide CMP of a pre-metal dielectric (PMD) prior to forming any contacts. The formation of the feature structure may include the formation of shallow trench isolation (STI). The formation of the damascene interconnects may include the formation of tungsten "plug" contacts or the formation of copper "trench" or copper "via" connections. In a specific example, copper metal is deposited prior to the CMP process by electroplating and annealing, and the copper metal includes an "overburden" or an excess of material. Annealing is performed to initiate grain growth of copper because large grain growth can reduce copper resistance. The position of the copper affects the grain size or the average grain size. The "cover layer" tends to grow into large grains in which the grains are not structurally restricted. However, the copper in the trenches and vias is structurally constrained, so the copper in the trenches and vias will grow into smaller grains. Thus, via annealing, the trench can form a large grain size with the copper on/in the via.

The CMP process has several drawbacks. First, a partial dishing may occur. 1 is a schematic cross-sectional view of a metal layer in which a local dishing is already present to illustrate the disadvantages of the prior art. Metal layer 401, which may be copper, tungsten, or some other metal, is disposed on layer 400. Layer 400 can be an interlayer dielectric (ILD) or an intermetal dielectric (IMD) such as hafnium oxide. Layer 400 can also be a low dielectric constant (low-k) dielectric such as Si-O-C. The polishing of layer 400 and metal layer 401 will vary due to differences in etch characteristics.

In addition, in the CMP process, two different metals may be ground at the same time. A metal, such as tantalum or nitride, can serve as a liner for the metal layer 401 or a diffusion barrier layer 413. A liner or diffusion barrier layer 413 may be required to prevent metal from diffusing into the layer 400 from the metal layer 401. In the CMP process, the metal layer 401, as well as the liner or diffusion barrier layer 413, can be simultaneously ground. Differences in density and hardness of various materials will cause the polishing rate to vary from material to material. As such, excess copper will be removed from the metal layer 401. Excess copper will be removed from the metal layer 401 as compared to the desired surface shown by line 406. Holes 405 will be formed and will be effectively reduced. The thickness of the metal layer 401.

Second, dishing or microloading can occur. 2 is a schematic cross-sectional view of a metal layer in which a local dishing is already present to illustrate the disadvantages of the prior art. Metal layer 402 is wider than metal layer 403. In this example, both the metal layer 402 and the metal layer 403 are copper, but other metals may be used. For example, a wide metal line of metal layer 402 may be ground more than a narrow metal line such as metal layer 403, which will result in more metal being removed in the wide metal region and making the wide metal region thinner. . A wide metal line, such as metal layer 402, may have larger grains than narrow metal lines such as metal layer 403 because these lines are less structurally constrained by trenches or vias. Performing a CMP process on a metal layer with smaller grains may mean that the sulphur chemistry will attack the higher density grain boundaries or the interface between the two different metals. Performing a CMP process on a metal layer with larger grains may mean that the slurry chemistry is an abrasive. Thus, a wider metal line, such as metal layer 402, has larger grains than a narrower metal line such as metal layer 403, tending to be polished at a different, or faster, rate. In the wider metal layer 402, a larger hole 407 will be formed with respect to the ideal surface shown by line 406, as compared to the hole 408 in the narrower metal layer 403. Where all other conditions are equal, a wider metal line, such as metal layer 402, will have larger grains and the dishing will be larger.

Third, erosion can occur. Figure 3 is a schematic cross-sectional view of a metal layer in which etching has been present to illustrate the shortcomings of the prior art. In contrast to isolated features, such as region 412 where metal line 404 is located, the loading effect of the CMP process will grind dense regions, such as region 411 where metal line 404 is located, at different rates. If the metal line 404 is in a denser case, the metal line 404, which may be copper or other metal, and the layer 400, which may be ILD or IMD, may be removed or ground more in the CMP process because Closed areas tend to be eroded more. Thus, with respect to the ideal surface shown by line 406, a hole 410 will be formed in region 411, while hole 410 is larger than hole 409 in region 412.

Fourth, because the CMP process is performed in a different manner, the CMP process tends to have a faster polishing rate at the center of the workpiece or a greater amount of polishing than the edge of the workpiece. The compression of the edge of the pad may vary compared to the center of the pad, which will cause variations in the thickness of the edge in the workpiece. For example, in oxide polishing, the edge of the workpiece may be ground at a slower rate or less ground than the center of the workpiece. This condition can generally be compensated by the opposite profile distribution during the chemical vapor deposition (CVD) process or the metal deposition process.

The CMP process performed on a metal surface has a number of disadvantages. Although these examples are especially about copper, other metals and materials, such as dielectrics, suffer from similar problems. As the size shrinks, problems caused by the CMP process, such as dishing, grooves, erosion, or CMP non-uniformity, become more severe because of the sensitivity of the metal's resistance to thickness.

First, the results of the CMP process are not uniform across the workpiece. More specifically, there will be differences between wafers after the CMP process. This means that there will be a difference in reliability between different wafers on the same workpiece. Some integrated circuits that are susceptible to CMP processes may even fail as a result of the CMP process. In addition, a single CMP process can result in yield losses of approximately 2 to 4%, and sometimes, up to 20% of non-conformity losses can be caused by these problems. Yield loss is a measure of whether a wafer is "good" or "bad" on a wafer. A "good" chip is considered part of the yield. Compliance loss is any error in the IC that results in an undesirable shape or shape. For example, if a dielectric profile should be planar, but has a dishing depression after the CMP process, the IC has a loss of compliance.

Therefore, in the art, it is necessary to find a solution to the above inapplicability and disadvantages, and in particular, an implantation method which can improve the results of the CMP process.

According to a first aspect of the invention, a method is proposed. This method involves depositing metal on the surface of the workpiece. The substance is implanted into the metal to amorphize at least a portion of the metal. Chemical mechanical polishing is performed on the surface exposed by the metal.

According to a second aspect of the invention, a method is proposed. This method involves depositing a layer on the surface of the workpiece. The substance is implanted into at least a portion of this layer. The surface exposed on this layer is subjected to chemical mechanical polishing.

According to a third aspect of the invention, a method is proposed. The method includes implanting a first substance into a workpiece to form a layer of microbubbles in the workpiece. The workpiece is cleave along the microbubble layer to form a cut surface. The second substance is implanted into at least a portion of the cut surface. Chemical mechanical polishing is performed on the cutting face.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

In one embodiment, the results of the CMP process can be improved by ion implantation. Ion implantation can be performed, for example, by a plasma doping system or a beamline ion implanter. 4 is a block diagram of a plasma doping system 100. FIG. 5 is a block diagram of a beam line ion implanter 200. It is understood by those skilled in the art that the plasma doping system 100 and the beam line ion implanter 200 are only a few examples of different plasma doping systems and beam line ion implanters, respectively, which can improve the CMP process results. One. This process can also be performed using other ion implantation systems, or other workpieces, or semiconductor wafer processing equipment. Although, in many embodiments, germanium workpieces are discussed, the process can also be applied to workpieces composed of SiC, GaN, GaP, GaAs, polysilicon, Ge, quartz, or other materials known to those of ordinary skill in the art. on.

Referring to FIG. 4, the plasma doping system 100 includes a process chamber 102 that defines an enclosed volume 103. A platform 134 can be placed in the process chamber 102 to support the workpiece 138. A bias voltage can be applied to the platform 134 using a direct current (DC) or radio frequency (RF) power supply. The platform 134, the workpiece 138, or the process chamber 102 can be cooled or heated by a temperature adjustment system (not shown). In one example, the workpiece 138 can be a semiconductor wafer having a disk shape, in one embodiment, for example, a tantalum wafer having a diameter of 300 mm. However, the workpiece 138 is not limited to a tantalum wafer. For example, workpiece 138 can also be a flat panel, solar or polymeric substrate. The workpiece 138 can be clamped to the plane of the platform 134 using electrostatic or mechanical forces. In an embodiment, the platform 134 can include conductive pins (not shown) to create a connection with the workpiece 138. The plasma doping system 100 further includes a plasma source 101 configured to produce a plasma 140 in the process chamber 102. The plasma source 101 can be an RF plasma source, or other source of plasma known to those of ordinary skill in the art. The plasma doping system 100 may further include a shield ring, a Faraday sensor, or other components. In some embodiments, the plasma doping system 100 is part of a cluster tool, or there are multiple operatively-linked electricity in a single plasma doping system 100. Slurry doping chamber. Therefore, many plasma doping chambers can be joined together in a vacuum.

In operation, the plasma source 101 is configured to produce a plasma 140 in the process chamber 102. In one embodiment, the plasma source is an RF plasma source that resonates the RF current in at least one of the RF antennas to produce an oscillating magnetic field. This oscillating magnetic field causes the RF current to enter the process chamber 102. The RF current in the process chamber 102 excites and ionizes a gas to produce a plasma 140. The bias applied to the platform 134, and thus to the workpiece 138, will accelerate ions from the plasma 140 toward the workpiece 138 in a plurality of periodic bias pulses. The frequency of the pulsed platen signal and/or the duty cycle of the pulse can be selected to provide the desired dose rate. The amplitude of the pulsed platform signal can be selected to provide the required energy. With all other parameters being the same, higher energy will result in a deeper implant depth.

Referring to FIG. 5, a block diagram of a beam line ion implanter 200 is shown. Again, those of ordinary skill in the art will recognize that beamline ion implanter 200 is only one of many examples of beamline ion implanters that can provide ions. In general, beamline ion implanter 200 includes ion source 280 to generate ions, and these ions can be extracted to form ion beam 281. For example, ion beam 281 can be a ribbon beam or a spot. Spot beam. In one example, ion beam 281 can be mass analyzed and can be converted by a diverging ion beam into a ribbon beam that is substantially parallel to the ion orbit. In some embodiments, the beamline ion implanter 200 can further include an acceleration or deceleration unit 290.

An end station 211 supports one or more workpieces, such as workpiece 138, on the path of ion beam 281 to cause ions of the desired species to be implanted into workpiece 138. In one example, the workpiece 138 can be a semiconductor wafer having a disk shape, in one embodiment, for example, a tantalum wafer having a diameter of 300 mm. However, workpiece 138 is not limited to germanium wafers. For example, workpiece 138 can also be a flat panel, solar or polymeric substrate. The terminal station 211 can include a platform 295 to support the workpiece 138. In an embodiment, the end station 211 may also include a scanner to move the workpiece 138 perpendicular to the length of the ion beam 281 profile, thereby allowing ions to be distributed throughout the surface of the workpiece 138.

The beamline ion implanter 200 can include additional components known to those of ordinary skill in the art, such as automated workpiece handling equipment, Faraday sensors, or electron flood guns. Gun). It will be understood by those of ordinary skill in the art that the entire path through which the ion beam passes is a vacuum during ion implantation. In some embodiments, the beamline ion implanter 200 can include thermal or cold implantation of ions.

The use of ion implantation can overcome the limitations and disadvantages of using CMP. For example, ion implantation using the plasma doping system 100 or the beamline ion implanter 200 can be performed before/in the CMP step, or before/in the plurality of CMP steps, and can be improved on the metal. The CMP process results, while the metal includes, for example, copper. However, ion implantation will also improve the CMP process results on other metals or conductors. In a particular example, ion implantation will amorphize a portion of the deposited and annealed copper on the surface of the metal layer or cause the crystal lattice of the material to become cluttered or irregular. The amorphous material has an amorphous structure. Since the ion implantation process does not have a microloading effect or a difference between an isolated feature structure and a dense array feature structure, the nature and depth of the amorphization are not affected by the size of the feature structure. Influenced by density, depth or depth.

The amorphization process can eliminate the dependence of grain size and polishing rate and can improve the hardness of copper to reduce copper erosion. CMP is affected by grain size because in the CMP process, the chemistry of the slurry attacks the grain boundaries of smaller grain sizes, while at larger grain sizes, the chemistry of the slurry can be an abrasive. If the copper is amorphized, the copper will have no grain boundaries because the grain size will only be found in the crystalline material. The degree of amorphization or the proportion of the surface being amorphized also affects the CMP process. For example, a more amorphized surface can further improve the results of the CMP process. A more amorphous surface will also affect or improve the results of other grinding methods.

6(A) to (B) are schematic cross-sectional views of a metal layer before the CMP process and after the CMP process. Figure 6 (A) is before the CMP process. Metal layer 301 and metal layer 302 are located in layer 400. Although the metal layer 301 and the metal layer 302 are adjacent to each other for comparison, the metal layer 301 and the metal layer 302 may be located on different workpieces or on different portions of a workpiece. At least a portion of the metal layer 302 is amorphized as shown by region 303. Figure 6 (B) is after the CMP process. The presence of the amorphized region 303 will improve the CMP process results of the metal layer 302 as compared to the metal layer 301. Metal layer 301 will have holes 304 compared to the ideal profile shown by line 305.

Using the energy control of ion implantation, the depth at which copper is amorphized can be controlled, and the extent of dishing of copper can thus also be controlled. If the implant depth is too shallow, the result of the CMP process may still have dishing defects, since at least some of the amorphized areas of copper will be removed during the CMP process. Thus, only copper that has not been amorphized remains as the subject of the CMP process. Therefore, if all of the regions of copper that are removed during the CMP process are amorphized, the dishing can be completely controlled. If only the copper portion that would be removed during the CMP process is amorphized, some dishing may occur. Compared to copper, which is not amorphized, in this example, there may be fewer dishings.

The energy of ion implantation will vary with the depth of implantation required. For example, copper may only be implanted in shallow regions that are close to the surface of metal layer 302 that would be affected by the CMP process, such as region 303. In another example, copper is implanted to a deeper depth, such as the bottom of metal layer 302. In some embodiments, layer 400 can also be implanted.

For example, the energy required to implant into a dielectric is approximately 5 to 40 kiloelectron volts (keV). The energy required to implant into the metal varies depending on where the metal is in the CMP process. If an implant is performed at least partially during the CMP process or is performed midway through the CMP process, the implant requires less energy because some of the metal has been removed during the CMP process, and The required implant depth is shallow. The dose for this implant is approximately 1E14 and 1E16.

Ion implantation improves the results of the CMP process and improves component performance. The recesses and dishing defects of the formed metal lines can be reduced, and thus the line resistence and the resistance difference can be improved. The line resistance of the metal is an inverse function of the thickness of the metal, and thus the thickness variation caused by the uneven CMP process results in a change in resistance. In addition, it can reduce the erosion, micro-load caused by the CMP process, or the density, size and area dependence of the CMP process.

Accurate amorphous implants implanted to certain depths can be used to aid electromigration and improve the results of the CMP process. Precise amorphous implantation allows the grains in the metal to be removed. In metals, the grain boundaries between different grains lack the symmetry of the normal lattice. Electrons flowing through the grain boundaries will transfer more momentum to the lattice atoms on the grain boundaries because the lattice atoms on the grain boundaries are asymmetrical. Removing the grains from the metal by amorphization will reduce the number of atoms that are struck by the flowing electrons, since the momentum transferred to the atoms will be reduced, thus reducing electromigration. In addition, only a certain depth or only a certain area of amorphization avoids contamination of non-metallic areas.

Finally, the surface of the amorphized metal can also improve the adhesion between the metal surface and the subsequently deposited protective or etch stop layer, the subsequently deposited protective layer or etch stop layer being, for example, SiN. Part of the protective layer or etch stop layer is amorphous and dielectric. If the metal is amorphized, the interfacial adhesion of the metal-dielectric can be improved because the stress is reduced, the wettability is improved, and the surface area is increased.

Figure 7 is a flow chart of a first embodiment of ion implantation to improve the CMP process results. In this particular embodiment, the structure that is ion implanted includes a copper layer. However, other structures, metals or conductors can be used in this process. In this embodiment, copper ion implantation 701 occurs after copper deposition and annealing 700, but copper ion implantation 701 occurs prior to any CMP process. The depth of implantation can vary. In one embodiment, the implant depth can be chosen to be just above any barrier or dielectric layer in the structure such that only a copper overlay is implanted. In another embodiment, the implant depth can be selected to be lower than any barrier or dielectric layer in the structure.

The CMP process 702 occurs after ion implantation. This CMP process 702 can include multiple stages in one instance or can occur in multiple steps. As explained herein, in the CMP process 702, the presence of amorphous copper will help reduce dishing and reduce the erosion of the copper features in the structure.

Figure 8 is a flow chart of a second embodiment of the results of ion implantation to improve the CMP process. In this particular embodiment, the ion implanted structure comprises a copper layer. However, other structures, metals or conductors can be used in this process. In this embodiment, copper ion implantation 802 occurs after copper deposition and annealing 800, and after at least a portion of the copper cap layer is removed 801, but before CMP process 803 is completed. The copper cap layer can be removed by CMP, or for example, electrolytic CMP (E-CMP) can be used. E-CMP is a reverse electroplating process in which copper is dissolved from the surface into an electroplating bath. After ion implantation 802, CMP process 803 is completed. In one example, completing the CMP process 803 includes multiple stages or can occur in multiple steps. In CMP process 803, the presence of amorphous copper will help reduce dishing and reduce erosion of the features of the copper in the structure.

In the particular embodiment of Figure 8, only a fragile implant can occur in the dielectric material between the features of the copper when the amorphized ions are implanted 802. Since the material around the barrier metal or copper is denser and harder than copper, the implanted area in the barrier metal is shallower than in copper. Therefore, implantation at a particular energy will be implanted in copper deeper than the barrier metal or material surrounding the copper. The material implanted into the barrier metal or copper may be shallow. For example, in Figure 6A, region 303 is deeper than implanted layer 400. The barrier metal, as shown in Figure 1, can be Ta, TaN or TiN, and the barrier metal acts as a mask for any implanted ions and can prevent these ions from reaching the dielectric layer. In the characteristic structure of copper, the thickness of the amorphized region can be designed to improve the uniformity of the results in subsequent stages of the CMP process. For example, the thickness of the amorphized region can be at least the same as the thickness of the material removed during the CMP process to improve the uniformity of the results.

In other embodiments, ion implantation occurs at a later stage in the CMP process. Embodiments of the processes described herein are not limited to the methods illustrated in Figures 7 and 8.

In the embodiments of FIGS. 7 and 8, the type of ions may be, for example, Si, Ge, Ar, As, He, H, B, P, C, another indebted gas, or a molecular substance including C, B. And H, for example, carborane C ₂ B ₁₀ H ₁₁ . The type of ions may also be a cluster of carbon molecules, a macromolecular substance or another substance. The energy used in the implantation can depend on the substance selected and the depth of implantation required. For example, for a 45 nm (nano) logic structure, the copper cap layer can be approximately 5-6 μm (microns). After most of the copper cap layer is removed in the CMP process, the remaining copper cap layer can be approximately 50 nm thick. In the range of copper, Ta and TaN have a parasitic resistance of about 0.5 Rp. These materials are also suitable for other implants that improve the results of the CMP process.

Implantation can be performed at room temperature, or, in some embodiments, the implantation can be thermal or cold implantation. Higher or lower temperatures improve the depth of implantation by changing the spacing of atoms in the crystal lattice, or the quality of the amorphization. For example, cold implants may be beneficial because colder implants can increase the depth of amorphization at lower doses. Lower workpiece temperatures will lower the threshold for the material to amorphize the workpiece and also improve the quality of the amorphization. The quality of the amorphization is improved at lower temperatures because the crystal lattices of the workpieces can be relatively close to each other compared to the lattice at higher temperatures. Since the amorphization threshold is lowered, cold implantation can also reduce the dose required for amorphization. Cold implantation can improve the quality of amorphization since more amorphization can occur at a given dose.

Moreover, in these embodiments, any amorphized regions remaining on the surface of the features of copper may also improve electromigration. The amorphous surface of copper may also have better adhesion to a protective layer such as a nitride or an etch stop layer. Therefore, implanted materials can be selected to improve the uniformity of the CMP process and to improve electromigration and adhesion.

By implanting a dopant species, such as B, P or As, this implantation can improve the results of the CMP process and can be doped with a copper layer. Figure 9 is a schematic illustration of a copper layer in which a copper layer has been implanted with a substance. The copper layer 1401 and the cover layer 1404 of the workpiece 138 have been implanted in an implanted region by a dopant, wherein the dopant is, for example, B, P or As, and the implanted region extends along the line 1400. . The excess or cap layer 1404 will be removed down to line 1403 in the CMP process. This will leave a portion of the implanted area extending toward line 1400. Thus, a portion of the workpiece 138 can be doped while improving the CMP process results. Dielectric material 1402 can also be doped with this species. Although the dielectric 1402 and the copper layer 1401 shown in FIG. 9 are doped to the same depth, in another example, the implantation depth into the dielectric 1402 and the implantation depth into the copper layer 1401 are different. If the dielectric 1402 is doped, the reactivity of the dielectric 1402, or the wet etch rate of the dielectric 1402 in the slurry, can be reduced. In another embodiment, a substance such as C is implanted into the copper layer 1401 and the dielectric 1402. Implantation of carbon into the dielectric 1402 reduces the dielectric constant of the dielectric 1402, or the k value of the dielectric 1402.

As noted above, other metals may also benefit from this ion implantation process. For example, this process can be applied to tungsten. However, this process can be applied to other specific CMP processes, such as CMP processes for crystals, dielectrics, or polymers. Amorphization caused by ion implantation will at least affect dishing, erosion, and polishing rates.

In an embodiment, the ion implantation process can be applied to the PMD. Figure 10 is a schematic cross-sectional view of a PMD in which the PMD is implanted to improve the results of the CMP process. The PMD 1600 includes a polysilicon layer 1601, a source 1602, and a drain 1603. In an example, the polysilicon layer 1601 can be a gate. PMD 1600 also includes layer 1604, which may be a dielectric or oxide. The PMD 1600 may have other designs than those shown in FIG. 10, and is not limited to the embodiment shown in FIG. In the CMP process, layer 1604 will be ground. Implanting ions into at least the surface 1605 of the layer 1604 will improve the results of the CMP process. In some embodiments, surface 1605 of layer 1604 can be amorphized. This will affect at least the dishing, erosion and grinding rate.

In another embodiment, the ion implantation process can be applied to an STI. Figure 11 is a schematic cross-sectional view of an STI in which the STI is implanted to improve the results of the CMP process. The STI 1700 includes a structure 1701, which in the present embodiment has two trenches 1703, 1704. These trenches 1703, 1704 and surface 1705 of structure 1701 are covered in layer 1702, which may be a dielectric or oxide. The STI 1700 may have other designs than those shown in FIG. 11, and is not limited to the embodiment shown in FIG. In the CMP process, layer 1702 will be ground down to surface 1705 of STI 1700 such that only trenches 1703, 1704 will be filled by layer 1702. The implantation of layer 1702 will improve the results of the CMP process. In some embodiments, layer 1702 can be amorphized. This will affect at least the dishing, erosion and grinding rate.

The implanted layer shown in Figures 10 and 11 can be any crystal or any dielectric such as, for example, an oxide, a carbide or a nitride. Therefore, the process is not limited to oxides, carbides or nitrides.

In another embodiment, the implanted dose can be varied such that the center of the workpiece is subjected to more implants than the edge is subjected to. In a CMP process, the center of the workpiece is typically ground more than the edge because the compression of the edge of the pad may be different from the center of the pad. Figure 12 is a plan view and corresponding cross-sectional view of an embodiment in which the implant dose on the workpiece is different. The intermediate region 900 of the workpiece 138 is implanted by a higher dose than the edge region 901 of the workpiece 138. In implantation, the ion dose, scan rate, scan pattern, beam current, or beam energy can be varied to form a central region 900 and an edge region 901. Other patterns that vary the dose across the workpiece 138 are also possible, such as a dose that is high or low along the width of the workpiece 138, or a gradient from the center to the edge of the workpiece 138.

In other embodiments, both sides of the workpiece can be implanted to improve the results of the CMP process. In this particular embodiment, both sides of the workpiece will be ground. In a particular embodiment, both sides of the workpiece are simultaneously ground.

Ion implantation can also increase or decrease the polishing rate in the CMP process. The polishing rate can be accelerated or decelerated by implanting a surface as compared to a CMP process in which the workpiece is not implanted. If the grinding is accelerated, the CMP process will take less time and use less slurry. In a specific example, accelerating the CMP process after implantation will reduce the use of slurry by 10%. In one embodiment, to accelerate the grinding in the CMP process, the substance is implanted onto the surface, such as B, P, As or another active dopant. In another embodiment, to decelerate the grinding in the CMP process, an inert gas is implanted into the surface, such as H or blunt gas.

Implantation using an inert gas such as H or blunt gas can create microbubbles in the workpiece. Figure 13 shows a workpiece that has been implanted with an inert gas. Substance 1500, such as H or blunt gas, is implanted into workpiece 138. Microbubbles 1501 or microvoids are formed near the surface of the workpiece 138. The depth of the microbubbles 1501 or the range of microbubbles 1501 can be adjusted by varying the parameters of the implant, such as implant energy or implant dose. Since the microbubbles 1501 are present in the vicinity of the surface 1502 at a high dose, the surface 1502 of the workpiece 138 may be brittle or porous, which may affect the CMP process. In other embodiments, the substance 1500 is implanted at a low dose, and metal atoms in the workpiece 138 will diffuse to repair any defects in the workpiece 138, such as microbubbles 1501. Thus, the microbubbles 1501 will be absorbed or destroyed prior to the CMP process, while the material 1500 will be incorporated into the crystal lattice of the workpiece 138. The workpiece 138 can also be heated and the material 1500 diffused out of the workpiece 138.

In yet another example, embodiments of the present ion implantation method can be applied to grinding a cut workpiece, or to a 3D IC or stacked wafer. Prior to cutting, such a workpiece has been implanted using hydrogen or helium to form microbubbles. The surface formed after dicing is rough and requires grinding in the CMP process. Implantation will at least affect the dishing, erosion, and polishing rates of the CMP process.

14(A) to (E) are schematic cross-sectional views showing an embodiment of cutting. Implantation prior to the CMP process or during the CMP process is applied to structures that require cutting implants, such as 3D ICs or stacked wafer structures. This process can also be applied to the manufacture of workpieces such as flat panels, films, solar cells, light-emitting diodes (LEDs), other thin metal sheets, or other components. The workpiece cut using this process may be, for example, tantalum, SiC, GaN, GaP, GaAs, polysilicon, Ge, quartz, or other materials.

A workpiece 138 is provided to produce the workpiece to be cut, as shown in Figure 14(A). The workpiece 138 can be a donor wafer. For example, at least one substance 1000, such as hydrogen or helium, is implanted into the workpiece 138 to form the microbubble layer 1001, as shown in Figure 14(B). In the annealing or other heat treatment, the workpiece 138 may be broken or cracked along the microbubble layer 1001 as shown in Fig. 14(C). In another embodiment, mechanical, chemical, or fluid forces may be used to break or split the workpiece 138 along the microbubble layer 1001. In some embodiments, the remaining workpiece 138 after splitting can be reused. In another particular embodiment, the workpiece 138 is first bonded to another workpiece prior to breaking or cracking the workpiece 138 along the microbubble layer 1001.

Then, any side of the cracked workpiece 138 is implanted using the second substance 1002 as shown in Fig. 14(D). The second substance 1002 can be the same as the first substance 1000, and this second substance 1002 can control the effect of the CMP process on the workpiece 138 being cut. The workpiece 138 to be cut is then ground in a CMP process to make the surface smooth enough for component fabrication, as shown in Figure 14(E). The implantation of the second substance 1002 will at least affect the dishing, erosion, and polishing rate of the CMP process.

15(A) to (G) are schematic cross-sectional views showing an embodiment of a silicon-on-insulator (SOI) wafer fabrication. Wafer fabrication can be improved by implanting a substance prior to the CMP process or during the CMP process. Embodiments of this implantation method can be applied to other embodiments of SOI wafer fabrication, and are not limited to the method illustrated in FIG.

A workpiece 138 is provided to fabricate the SOI wafer as shown in Figure 15(A). The workpiece 138 can be a donor wafer. This workpiece 138 has a thermal oxide layer 1100 formed on at least one surface as shown in Fig. 15(B). For example, at least one substance 1000, such as hydrogen or helium, is implanted into the workpiece 138 to form the microbubble layer 1001, as shown in Figure 15(C). This workpiece 138 is then inverted and bonded to the handle wafer 1102 and annealed as shown in Figure 15(D). In some embodiments, the workpiece 138 will be cleaned prior to bonding the workpiece 138 to the handle wafer 1102. During annealing or additional heat treatment, the workpiece 138 will break or rupture along the microbubble layer 1001, as shown in Figure 15(E). In another embodiment, mechanical, chemical, or fluid forces may be used to break or split the workpiece 138 along the microbubble layer 1001. In some embodiments, the remaining workpiece 138 after splitting can be reused.

Next, the second layer 1002 is implanted into the upper layer 1103 of the SOI wafer 1101 as shown in FIG. 15(F). The second substance 1002 can be the same as the first substance 1000, and the second substance 1002 can control the effect of the CMP process on the upper layer 1103. Next, the formed SOI wafer 1101 is ground in a CMP process to make the surface smooth enough for component fabrication; the SOI wafer 1101 includes a thermal oxide layer 1100 and an upper layer 1103, as shown in FIG. 15(G). The implantation of the second substance 1002 will at least affect the dishing, erosion, and polishing rate of the CMP process.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100. . . Plasma doping system

101. . . Plasma source

102. . . Process chamber

103. . . Closed volume

134. . . platform

138. . . Workpiece

140. . . Plasma

200. . . Beam line ion implanter

211. . . Terminal station

280. . . source of ion

281. . . Ion beam

290. . . Acceleration or deceleration unit

295. . . platform

301, 302, 401, 402, 403. . . Metal layer

303, 411, 412. . . region

304, 405. . . Hole

305, 406. . . line

400, 704, 802. . . Floor

404. . . metal wires

407, 408, 409, 410. . . Hole

413. . . Liner or diffusion barrier

700~702, 800~803. . . step

900. . . Intermediate area

901. . . Edge area

1400, 1403. . . line

1401. . . Copper layer

1402. . . Dielectric

1404. . . Cover layer

1000, 1500. . . substance

1001. . . Microbubble layer

1002. . . Second substance

1103. . . upper layer

1100. . . Thermal oxide layer

1102. . . Operating wafer

1501. . . Microbubble

1600. . . PMD

1601‧‧‧Polysilicon layer

1602‧‧‧ source

1603‧‧‧Bungee

1605, 1705‧‧‧ surface

1700‧‧‧STI

1701‧‧‧ structure

1703, 1704‧‧‧ trench

1 is a schematic cross-sectional view of a metal layer in which a local dishing is already present to illustrate the disadvantages of the prior art.

2 is a schematic cross-sectional view of a metal layer in which a local dishing is already present to illustrate the disadvantages of the prior art.

Figure 3 is a schematic cross-sectional view of a metal layer in which etching has been present to illustrate the shortcomings of the prior art.

Figure 4 is a block diagram of a plasma doping system.

Figure 5 is a block diagram of a beam line ion implanter.

6(A) to (B) are schematic cross-sectional views of a metal layer before the CMP process and after the CMP process.

Figure 7 is a flow chart of a first embodiment of ion implantation to improve the CMP process results.

Figure 8 is a flow chart of a second embodiment of the results of ion implantation to improve the CMP process.

Figure 9 is a schematic illustration of a copper layer in which a copper layer has been implanted with a substance.

Figure 10 is a schematic cross-sectional view of a PMD in which the PMD is implanted to improve the results of the CMP process.

Figure 11 is a schematic cross-sectional view of an STI in which the STI is implanted to improve the results of the CMP process.

Figure 12 is a plan view and corresponding cross-sectional view of an embodiment in which the implant dose on the workpiece is different.

Figure 13 shows a workpiece that has been implanted with an inert gas.

14(A) to (E) are schematic cross-sectional views showing an embodiment of cutting.

15(A) to (G) are schematic cross-sectional views showing an embodiment of the SOI wafer fabrication.

301, 302. . . Metal layer

303. . . region

304. . . Hole

305. . . line

400. . . Floor

Claims (23)

A method of improving the uniformity of chemical mechanical polishing planarization, comprising: depositing a metal on a surface of a workpiece; implanting a substance into the metal to amorphize at least a portion of the metal, wherein the surface is A different dose of the substance is received at a second location on the surface; and chemical mechanical polishing is performed on the exposed surface of the amorphized metal. The method of improving the uniformity of planarization of chemical mechanical polishing as described in claim 1, wherein the metal is selected from the group consisting of copper and tungsten. The method of improving the uniformity of planarization of chemical mechanical polishing as described in claim 1, wherein the substance is selected from the group consisting of Si, Ge, As, B, P, H, He, Ne, Ar, Kr, Xe And the group of C group. The method for improving the uniformity of planarization of a CMP by the method of claim 1, wherein the method for improving the uniformity of planarization of the CMP includes the controlling the amorphization in the metal Electromigration. The method of improving the uniformity of planarization of chemical mechanical polishing according to claim 1, wherein the method for improving the uniformity of planarization of the chemical mechanical polishing further comprises controlling the metal with the amorphization The adhesion of one layer. Improved chemical mechanical polishing as described in claim 1 A method of homogenizing uniformity, wherein the amorphization occurs prior to the chemical mechanical polishing. The method of improving the uniformity of planarization of a CMP by the method of claim 1, further comprising removing the covering layer of the metal on the workpiece. A method for improving the uniformity of planarization of a CMP by the method of claim 7, wherein the amorphization occurs after removing a coating of the metal on the workpiece, but the amorphization This occurs before the chemical mechanical polishing. The method of improving the uniformity of planarization of chemical mechanical polishing as described in claim 1, wherein the substance is selected from the group consisting of As, B, and P, and is compared to a rate at which the workpiece is not implanted. The CMP is performed at an acceleration rate. The method of improving the uniformity of planarization of chemical mechanical polishing according to claim 1, wherein the substance is selected from the group consisting of H, He, Ne, Ar, Kr, and Xe, and compared to The rate at which the chemical mechanical polishing is performed is at a rate of deceleration. A method of improving the uniformity of planarization of chemical mechanical polishing as described in claim 1, wherein the first portion is an intermediate portion and the second portion is an edge region. The method of improving the uniformity of planarization of chemical mechanical polishing as described in claim 11, wherein the intermediate region has a first dose, the edge region has a second dose, and the first dose is greater than the first Two doses. A method of improving the uniformity of chemical mechanical polishing planarization, comprising: depositing a layer on a surface of a workpiece; implanting a substance into at least a portion of the layer, wherein the first portion on the surface and the surface The second portion receives the different doses of the substance; and performs chemical mechanical polishing on the surface exposed by the layer. The method of improving the uniformity of planarization of chemical mechanical polishing according to claim 13, wherein the layer is selected from the group consisting of dielectrics and crystals. The method for improving the uniformity of planarization of chemical mechanical polishing according to claim 13, wherein the substance is selected from the group consisting of Si, Ge, As, B, P, H, He, Ne, Ar, Kr, Xe And the group of C group. A method for improving the uniformity of planarization of chemical mechanical polishing as described in claim 13, wherein the substance is selected from the group consisting of As, B, and P, and compared to the rate at which the workpiece is not implanted. The CMP is performed at an acceleration rate. The method for improving the uniformity of planarization of chemical mechanical polishing according to claim 13, wherein the substance is selected from the group consisting of H, He, Ne, Ar, Kr, and Xe, and compared to The rate at which the chemical mechanical polishing is performed is at a rate of deceleration. A method of improving the uniformity of planarization of chemical mechanical polishing as described in claim 13 wherein said first portion is an intermediate portion and said second portion is an edge region. The method of improving the uniformity of CMP polishing planarization as described in claim 18, wherein the intermediate region has a first dose, the edge region has a second dose, and the first dose is greater than the first Two doses. The method of improving the uniformity of planarization of chemical mechanical polishing according to claim 13, wherein the layer is amorphized by implantation, and the chemically mechanically polished the amorphized layer. . A method for improving the uniformity of CMP polishing planarization, comprising: implanting a first substance into a workpiece to form a microbubble layer in the workpiece; and cutting the workpiece along the microbubble layer to form a cut surface; Implanting a second substance into at least a portion of the cutting face; and performing chemical mechanical polishing on the implanted portion of the cutting face. The method of improving the uniformity of planarization of chemical mechanical polishing according to claim 21, wherein the second substance is selected from the group consisting of Si, Ge, As, B, P, H, He, Ne, Ar, Kr , the group of Xe and C groups. A method of improving the uniformity of planarization of a CMP according to claim 21, wherein the method further comprises changing a dose of the second substance on the workpiece.